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bioRxiv · 10.64898/2026.01.10.697647

Neuronal age drives β-sheet accumulation and, together with ApoE4, enhances synaptic Aβ localization in APPNL-F neurons

Konings, S. C.·Nyberg, E.·Martinsson, I. S.·Thakore, R.·Gouras, G. K.·Klementieva, O.
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Abstract

Amyloid-{beta} (A{beta}) accumulation and aggregation are defining features of Alzheimers disease (AD), but the earliest cellular events driving these processes remain poorly understood. Here, we investigate A{beta} dynamics in primary neurons derived from APPNL-F knock-in mice, which express human APP and A{beta} at endogenous (non-overexpressed) levels. Using correlative optical photothermal infrared (OPTIR) spectromicroscopy and immunofluorescence, we show that physiological APPNL-F expression is sufficient to drive intraneuronal A{beta} accumulation at synapses. Modelling neuronal aging through prolonged culture reveals a marked increase in synaptic A{beta} burden accompanied by {beta}-sheet-rich structural transitions Supplementation with astrocyte-derived apolipoprotein E (ApoE) isoforms demonstrates that ApoE4 markedly increases synaptic A{beta} accumulation while reducing {beta}-sheet content relative to untreated cultures, suggesting a potential shift toward less fibrillar species. Together, these findings establish APPNL-F neurons as a physiologically relevant system for dissecting early A{beta} pathology and show that both A{beta} quantity (accumulation) and quality (structural maturation) are regulated by aging and ApoE genotype. This work provides mechanistic insight into the earliest molecular events that may underlie synaptic vulnerability in AD.

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Konings, S. C., Nyberg, E., Martinsson, I. S., Thakore, R., Gouras, G. K., Klementieva, O.. 2026-01-12. Neuronal age drives β-sheet accumulation and, together with ApoE4, enhances synaptic Aβ localization in APPNL-F neurons. https://doi.org/10.64898/2026.01.10.697647

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